(DL3DL_{3} LAST MINUTE ADDITION TO THE PROGRAM) Q BRANCHES OF THE ν2\nu_{2} BAND OF 13C16O17O, 13C17O2, 13C417O18O^{13}C^{16}O^{17}O,\ ^{13}C^{17}O_{2}, \ ^{13}C4^{17}O^{18}O AND 13C18O2^{13}C^{18}O_{2}

Author Institution:A diode laser has been employed to examine the Q branch absorption lines of the $\nu_{2}$ band for the following $CO_{2}$ isotopes: $^{13}C^{16}O^{17}O,\ ^{13}C^{17}O_{2}, \ ^{13}C4^{17}O^{18}O$ AND $^{13}C^{18}O_{2}$, and $^{13}C^{18}O_{2}$. An analysis of the relative frequency spacing between the absorption lines yielded the following values for $\Delta B$ expressed in units of $10^{-3}$ $cm^{-1}$: 1.016(2) for $^{13}C^{16}O^{17}O, 0.964(1)$ for $^{13}C^{17}O^{2}$, 0.9163(3) for $^{13}C^{17}O^{18} O$ and 0.891(2) for $^{13}C^{17}O_{2}$. Values for $\nu_{o}$, the band origin, were also obtained by super-imposing on the spectra known absorption lines of $^{12}C^{16}O_{2}$ and $^{12}C^{16}O^{18}O$. The following values were obtained for $\nu_{o}: 645.7440(2)$ for $^{13}C^{16}O^{17}O, 643.0064(1)$ for $^{13}C^{17}O_{2}, 640.5680(1)$ for $^{13}C^{17}O^{18}O$ and 638.1149(5) for $^{13}C^{18}O_{2}$. The above listed errors for $\nu_{o}$ are associated only with the statistical fitting of the data; the absolute accuracy depends upon the $^{12}C^{16}O_{2}$ reference lines which are known to about $\pm 0.001$ $cm^{-1}$. A comparison of the diode laser results are made with previous measurements utilizing Fourier transform spectroscopy

DIODE LASER SPECTROSCOPY OF Q-BRANCHES AT 662−661cm−1662-661 cm^{-1}, OF CO2CO_{2} ENCRICHED IN 18O^{18}O AND 17O^{17}O

Author Institution: Applied Photochemistry Division, Los Alamos Scientific Laboratory, University of California; Molecular Physics Building, Institute for Physical Science and Technology, University of MarylandMeasurements have been made of the absorption of the absorption of $CO_{2}$ samples enriched in 18O and 17O by tunable diode lasers in the wave number region 662.2-$666.1 cm^{-1}$. The fundamental Q-branches of the $^{16}O^{12}C^{18}O, ^{16}O^{12}C^{17}O$ and $^{17}O^{12}C^{17}O$ molecules are well resolved, together with ``hot’’ Q branches and various R and P branch lines of other isotopic species; notably $^{18}O^{12}C^{18}$ and $^{17}O^{12}C^{18}O$. The molecular constants for the Q-branch $01^{1}0 \leftarrow 00^{0}0$ of $^{16}O^{12}C^{18}O$ have been calculated by a least mean square fit to lines j=1 to 16 to be: $\nu_{o}=662.3717 \pm 0.0003\ cm^{-1}$, $\Delta B=9.65 + 0.02 \times 10^{-4} cm^{-1}$ where $\nu_{o}$ has been fixed in absolute magnitude by assuming the $^{16}O^{12}C^{16}O$ line, $02^{2}0 \leftarrow 01^{10}$ P7, as a reference standard at $662.325 cm^{-1}$. More accurate values for $\Delta B$ and $\Delta D$ can be obtained by using the separation between several R lines and adjacent Q lines, and the known positions of the R lines relative to the origin to obtain: $\Delta B=9.685 \pm 0.002 \times 10^{-4} cm^{-1}$ and $\Delta D=2.2 \pm 0.1 \times 10^{-9} cm^{-1}$. Other molecular constant can be determined with highest precision by using low J, R and P branch lines as calibration standards, together with etalon spacing. The calculated line positions of the fundamental Q branch can be used as secondary standards to fit the hot bands

DIRECT MEASUREMENT OF TWO 13C16O2^{13}C^{16}O_{2} Q-BRANCHES USING A 16 μ\mum TUNABLE DIODE LASER

Author Institution: Los Alamos Scientific Laboratory, University of CaliforniaTwenty-two spectral lines of the $^{13}C^{16}O_{2}$ Q-branch at $617 cm^{-1}$ have been observed, and fitted by a cubic polynomial in $J(J + 1)$ to a standard deviation of $\pm \ 3 \times 10^{-4}$ $cm^{-1}$. Another Q-branch, at $630.7 cm^{-1}$, has been observed for 12 lines, and fitted to a linear polynomial in $J(J + 1)$ to $\pm \ 9 \times 10^{-4} cm^{-1}$. The resulting molecular constants are given in Table I. [FIGURE] In addition, the positions of several lines from other isotopes and other bands have been measured with great accuracy relative to the adjacent lines of the above Q-branches

HIGH RESOLUTION SPECTRA OF SIXTEEN Q BRANCHES IN THE ν9\nu_{9} FUNDAMENTAL OF ETHANE

Author Institution: Theoretical Division, Los Alamos Scientific Laboratory; Department of Physics and Astronomy, University of TennesseeThe Q branches $^{P}Q_{6}$ through $^{R}Q_{9}$ of the $\nu_{9}$ ethane fundamental at 821 $cm^{-l}$ have been resolved at $300^\circ K$ using tunable diode lasers. A preliminary analysis yields $\Delta B = (- 1.27 \pm 0.02) \times 10^{-3} cm^{-1}$. Several of the branches exhibit line splittings that may result from the tunneling of the hindered rotation of the ethane molecule

DIODE LASER SPECTROSCOPY OF SF6SF_{6} AN UPDATE

Author Institution: Los Alamos Scientific LaboratoryRecent work on the high-resolution spectroscopy of the stretching fundamental $\nu_{3}$ of $SF_{6}$ includes the following: 1. A complete analysis of the Q branch accounts for some 3000 transitions between 947.6 and $948.3 cm^{-1}$. The $SF_{6}$ transition pumped by the $CO_{2}$ P(16) laser line has been identified as Q(38) $F_{1}^{0} + E^{0} + F_{2}^{0}$. 2. The transition pumped by the $CO_{2}$ P(22) laser line at $942.38 cm^{-1}$ has been identified as belonging to P(84) of $SF_{6}$. 3. The Q branch and the low-J P- and R-branch lines of $^{33}SF_{6} (939.01$ $cm^{-1})$ have been measured and analysed. 4. From the laser diode spectra and other absorption measurements the transition dipole moment of $\nu_{3}$ of $SF_{6}$ is estimated to be 0.41 $\pm 0.03$ Debye

ANALYSIS OF THE Q-BRANCH REGION OF THE 3v33v_{3} OVERTONE OF UF6UF_{6}: THE IMPLIED STRUCTURE OF THE nν3n\nu_{3} LADDER.

$^{1}$ K.C. Kim. E. Griggs, and W.B. Person. Appl. Opt. 17. 2511 (1978). $^{2}$ G.A. Laguna. K.C. Kim, C.W. Patterson, M.J. Reisfeld. and D. M. Seitz, Chem. Phys. Lett. 75. 357 (1980). $^{3}$ K.T. Hecht, J. Mol. Spectrosc. 5, 390 (1960). $^{4}$ C.W. Patterson, B.J. Krohn, and A.S. Pine, J. Mol. Spectrosc. 88. 133 (1981). $^{5}$ J.P. Aldridge et al., J. Chem. Phys. 83, 34 (1985). Address: University of California, Los Alamos National Laboratory, Los Alamos, New Mexico 87545Author Institution:Diode laser spectra of slightly cooled $(256 K) UF_{6}$ gas at 3.5 torr were obtained in the $1875 cm^{-1} (3\nu_{3})$ region using a 10-m White-type cell built by Kim $et al..^{1}$ in which multiple reflections provided path lengths of 360-400 m. Some of these spectra were reported $earlier.^{2}$ Despite the intrinsic weakness of this absorption and the presence of very numerous hot bands at this temperature, we have identified several discrete features as belonging to the transition out of the ground state and have assigned their rotational quantum indices. The wavenumbers were fitted to the vibration-rotation Hamiltonian of $Hecht^{3}$ using an interacting-band $analysis.^{4}$ Derived values for $B\zeta_{3}$ and $\triangle B$ are consistent with corresponding values determined from the analysis of the $\nu_{3} fundamental.^{5}$ In addition, we now report Hecht's parameters $w^{0}_{3}. X_{33}. G_{33}$. and $T_{33}$ for the $n\nu_{3}$ vibrational overtone ladder of $UF_{6}$. The implied ladder structure will be discussed in terms of a ``local-type'' vs, a ``normal-type'' interpretation of the $\nu_{3}$ mode of vibration